Specific Heat of the Synthetic Rubber Hycar-OR from 15° to 340° K

1943 ◽  
Vol 16 (2) ◽  
pp. 310-317 ◽  
Author(s):  
Norman Bekkedahl ◽  
Russell B. Scott
Keyword(s):  
Heat Equation ◽  
Specific Heat ◽  
Temperature Curve ◽  
Second Order ◽  
Heat Temperature ◽  
A Value ◽  
Synthetic Rubber ◽  
Experimental Values ◽  
Adiabatic Vacuum

Abstract Measurements of specific heat were made on a sample of Hycar-OR synthetic rubber from 15° to 340° K by means of an adiabatic vacuum-type calorimeter. The experimental values of the specific heat between 15° and 22° K were well represented by the Debye specific-heat equation, using a βν value of 80 and, accordingly, the values below 15° K were calculated with this equation. At about 250° K the material has a transition of the second order, the specific heat increasing by about 40 per cent to a value of 1.84 Int. joules · gram−1 · degree−1 just above the transition. From 250° to 340° K the specific heat-temperature curve is nearly linear, and the values can be calculated to within 0.2 per cent from the formula Cp=0.00283T+1.126, in Int. joules · gram−1 · degree−1. At 298.16° K (25° C) the specific heat is 1.971 Int. joules · gram−1 · degree−1 (0.4712 calories · gram−1 · degree−1). The increase in entropy resulting from heating from 0° to 298.16° K was calculated to be 1.743 ± 0.002 Int. joules · gram−1 · degree−1 (0.4167 ± 0.0005 calories · gram−1 · degree−1).

BOSE–EINSTEIN CONDENSATION OF PARTICLES TRAPPED IN A BOUNDED HARMONIC POTENTIAL

2001 ◽  
Vol 15 (15) ◽  
pp. 2169-2191 ◽  
Author(s):  
SHALINI LUMB ◽  
S. K. MUTHU
Keyword(s):  
Finite Number ◽  
Specific Heat ◽  
Temperature Curve ◽  
Harmonic Potential ◽  
Einstein Condensation ◽  
Condensate Fraction ◽  
Eigenvalue Spectrum ◽  
Heat Temperature ◽  
Bose Einstein Condensation ◽  
Bose Einstein

The behavior of a finite number of bosons trapped in a bounded harmonic potential is investigated. The eigenvalue spectrum is worked out numerically for three different sizes of the trap. The condensate fraction is determined and is found to increase suddenly below a certain temperature which is a characteristic signature of BEC. The specific heat-temperature curve also shows a peak, with the maximum shifting to lower values and occurring at higher temperatures, as the size of the assembly is reduced.

THE FISSION BARRIERS OF HEAVY AND EXOTIC NUCLEI

2010 ◽  
Vol 19 (04) ◽  
pp. 514-520 ◽  
Author(s):  
FEDIR IVANYUK ◽  
KRZYSZTOF POMORSKI
Keyword(s):  
Liquid Drop ◽  
Optimal Shape ◽  
Exotic Nuclei ◽  
Fission Barrier ◽  
Heavy Nuclei ◽  
Accurate Approximation ◽  
Barrier Heights ◽  
A Value ◽  
Fission Barriers ◽  
Experimental Values

We have calculated the liquid drop fission barriers of medium and heavy nuclei within the Lublin-Strasbourg-Drop model. Exploiting in addition the topographical theorem by Myers and Światecki we propose a simple but quite accurate approximation of the fission barrier heights. When comparing the r.m.s. deviation of approximated versus experimental values of fission barrier heights for known nuclei with Z > 70 a value 1.1 MeV is obtained which is comparable with the experimental uncertainties. The Strutinsky optimal shape method is generalized to the left-right asymmetric shapes of nuclei in order to investigate the influence of this degree of freedom on the barrier heights.

An anomaly in the specific heat below 3 °K of copper containing hydrogen

1969 ◽  
Vol 47 (14) ◽  
pp. 1485-1491 ◽  
Author(s):  
Neil Waterhouse
Keyword(s):  
Specific Heat ◽  
Molecular Hydrogen ◽  
Pure Copper ◽  
Solid Hydrogen ◽  
Rotational State ◽  
Experimental Results ◽  
Ortho Hydrogen ◽  
Temperature Range ◽  
A Value ◽  
Heat Curve

The specific heat of copper heated in hydrogen at 1040 °C has been measured over the temperature range 0.4 to 3.0 °K and found to be anomalous. The anomaly occurs in the same temperature range as the solid hydrogen λ anomaly which, in conjunction with evidence of ortho to para conversion of hydrogen in the sample, suggests the presence of molecular hydrogen in the copper. The anomaly reported by Martin for "as-received" American Smelting and Refining Company (ASARCO) 99.999+ % pure copper has been briefly compared with the present results. The form of the anomaly produced by the copper-hydrogen specimen has been compared with Schottky curves using the simplest possible model, that for two level splitting of the degenerate J = 1 rotational state of the ortho-hydrogen molecule.Maintenance of the copper-hydrogen sample at ~20 °K for approximately 1 week removed the "hump" in the specific heat curve. An equation of the form Cp = γT + (464.34/(θ0c)3)T3 was found to fit these experimental results and produced a value for γ which had increased over that for vacuumannealed pure copper by ~2%.

scholarly journals Molecular Dynamics Calculation of the Thermodynamic Properties of Methane

1975 ◽  
Vol 28 (3) ◽  
pp. 315 ◽  
Author(s):  
HJM Hanley ◽  
RO Watts
Keyword(s):  
Molecular Dynamics ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Low Temperatures ◽  
Spherically Symmetric ◽  
Method Of Molecular Dynamics ◽  
Experimental Values ◽  
Dynamics Calculation ◽  
Liquid States ◽  
Three Body

Thermodynamic properties of methane in the dense gas and liquid states have been calculated by the method of molecular dynamics. The methane pair interactions were modelled using a spherically symmetric m-6-8 potential, and the most significant three-body and quantum effects were included. Agreement between calculated and experimental values for the energy and pressure is generally good except at low temperatures and high densities. The specific heat at constant volume is also briefly discussed.

Physical, Thermal and Water-Sorption Properties of Passion Fruit Seeds

2014 ◽  
Vol 10 (4) ◽  
pp. 785-798 ◽  
Author(s):  
Silvio J. Ferreira de Souza ◽  
Henry A. Váquiro ◽  
Harvey A. Villa-Vélez ◽  
Tiago C. Polachini ◽  
Javier Telis-Romero
Keyword(s):  
Thermal Properties ◽  
Specific Heat ◽  
Water Sorption ◽  
Effective Properties ◽  
Particle Density ◽  
Isosteric Heat ◽  
Second Order ◽  
Passion Fruit ◽  
Sorption Properties ◽  
Water Sorption Properties

Abstract Passion fruit seeds are an important by-product of the juice industry. In this study, physical, thermal and water-sorption properties of passion fruit (Passiflora edulis Sims f. flavicarpa Degener) seeds were determined. The knowledge of such properties is useful to design equipment or operations for storage or processing purposes. The physical properties of bulk density, particle density and bulk porosity, and the thermal properties of conductivity, diffusivity and specific heat were determined between water and mass fractions of 0.126 and 0.493. The thermal properties were determined for packed beds of seeds (effective properties), by means of which the thermal properties of the seeds (particle properties) were estimated. Different empirical models were evaluated for modeling the physical and thermal properties as function of moisture content. Physical and thermal properties were successfully described by a second-order polynomial, except by the specific heat which was described by a second-order logarithmic relationship. The isosteric heat, the differential entropy and the Gibbs free energy of water sorption were estimated using the Henderson model, which best fitted the experimental desorption isotherms at temperatures between 30°C and 70°C and relative humidities between 2% and 90%.

Wärmeleitfähigkeit, elektrische Leitfähigkeit, Hall-Effekt, Thermospannung und spezifische Wärme von Ag2Se

1962 ◽  
Vol 17 (10) ◽  
pp. 886-889 ◽  
Author(s):  
Y. Baer ◽  
G. Busch ◽  
C. Fröhlich ◽  
E. Steigmeier
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Low Temperature ◽  
Specific Heat ◽  
Thermoelectric Power ◽  
Hall Coefficient ◽  
A Value ◽  
Price Formula ◽  
Elektrische Leitfähigkeit ◽  
Increasing Temperature

The thermal conductivity, electrical conductivity. Hall coefficient und thermoelectric power of Ag2Se have been measured between 80 and 600°K. In the low temperature semiconductor phase the thermal conductivity increases with increasing temperature due to the high amount of carrier contribution. The latter has been calculated using the Price formula. Agreement with experiment is satisfactory. The specific heat has been measured between 30 and 200°C. For the latent heat a value of (5.7 ± 0.5) cal/gr was determined in agreement with measurements of Bellati and Lussana 4. In addition to the transition at 133 °C an unknown new transition has been found at about 90 °C.

SPECIFIC HEATS OF CERTAIN SALTS OF IRON GROUP ELEMENTS FROM 65° TO 300°K.

1950 ◽  
Vol 28a (4) ◽  
pp. 367-376 ◽  
Author(s):  
H. D. Vasileff ◽  
H. Grayson-Smith
Keyword(s):  
Low Temperature ◽  
Specific Heat ◽  
Cobalt Nitrate ◽  
Second Order ◽  
Nickel Nitrate ◽  
Chromium Nitrate ◽  
Iron Group ◽  
Anhydrous Salt ◽  
Specific Heats ◽  
Entropy Changes

Using a new low temperature calorimeter, which is briefly described in the paper, the specific heats have been measured from 65° to 300°K. for the following salts: chromium sulphate (hydrated and anhydrous), chromium nitrate, cobalt nitrate, and nickel nitrate (hydrated). Hydrated chromium sulphate was found to have a transition of the second order at 195°K., while the specific heat of the anhydrous salt was quite regular. The hydrated nitrates all showed second order transitions in the neighborhood of 150°K. The entropy changes associated with these transitions have been estimated approximately, and vary from about 0.4 R for cobalt nitrate to 1.65 R for chromium nitrate, where R is the gas constant. Pending further evidence, it is tentatively suggested that the transitions are due to the onset of partial rotation of the H2O groups in the crystals.

scholarly journals On the velocity of sound in gases at high temperatures, and the ratio of the specific heats

1921 ◽  
Vol 100 (702) ◽  
pp. 1-26 ◽  
Keyword(s):  
Specific Heat ◽  
High Temperatures ◽  
Velocity Of Sound ◽  
Specific Heats ◽  
A Value ◽  
Mean Temperature ◽  
Considerable Experience

The experiments described in this memoir on the velocity of sound in gases, at temperatures varying from atmospheric to that of a bright red heat, were made with the object of tracing the change in the specific heat of gases with rising temperature, and, if possible, of arriving at formulæ which might be applicable to the extremely high temperatures reached in explosions. The sound method was decided on chiefly for the reasons (1) that the velocity of sound in a heated gas gives a value for the ratio of the two specific heats at the temperature of the experiment, and not as in the method of mixtures at a mean temperature between the highest and lowest point of the heated and cooled gas; and (2) because we had had considerable experience in the use of a chronograph for measuring the rapid movements of flame through gases in long tubes. It is necessary to make it clear at starting that no claim is made that these experiments give more exact determinations of the specific heat of gases than those given previously by experiments over low ranges of temperature; the object has been to obtain by comparative measurements the general gradients of the curves rather than to find the exact value at any definite point.

scholarly journals Spezifische Wärme von CeCl3·7 H2O zwischen 1,1 und 3,3°K

1967 ◽  
Vol 22 (12) ◽  
pp. 1999-2001 ◽  
Author(s):  
S. Hüfner ◽  
R. v. Klot ◽  
F. Küch ◽  
G. Weber
Keyword(s):  
Triplet State ◽  
Specific Heat ◽  
Antiferromagnetic Coupling ◽  
Energy Separation ◽  
Temperature Range ◽  
A Value ◽  
Lower Singlet

The specific heat of monoclinic CeCl3 · 7 H2O was measured in the temperature range between 1,1 and 3,3°K. Assuming that the cerium-ions are arranged in isolated pairs with isotropic and antiferromagnetic coupling a value of k · 1,20°K is derived from the data for the energy separation between the lower singlet and the upper triplet state.

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